How to beat childhood cancer

The drugs being used to treat children with cancer were discovered in the 1950s and 1960s, and what is needed now
is the development of more effective, less toxic therapies

By Peter Adamson

Illustration: June Hsu

For a parent, there is perhaps no greater fear than the prospect of losing a child to illness or accident, and it is childhood cancer that has the greatest potential to catapult a remote fear into an unimaginable reality. As a pediatric oncologist, having cared for children with cancer and their families for more than 25 years, I know that only a parent who has confronted such a diagnosis truly understands the depth of this fear, as it touches the core of who we are as parents.

I also know that we are treating more children more effectively than ever before — and that we can do better still.

For a child born in the 1960s, the diagnosis of the most common form of childhood cancer, acute lymphoblastic leukemia (ALL), meant almost certain death, with a survival rate of less than 10 percent. A child with the same diagnosis today has a better than 80 percent chance of being cured. Looking at the five-year survival rates for children with ALL from the 1970s through the 1990s, one sees an almost linear improvement in cure rates.

This makes the 1970s, 1980s and 1990s look like an era of accelerating discovery and therapeutic development. However, virtually all of the drugs that we use today to cure children with cancer were discovered and approved in the 1950s and 1960s. So, if new drugs did not fuel four decades of progress, what did?

A major driver was a remarkable, sustained scientific collaboration. In the 1950s, a group of clinical scientists recognized that, because childhood cancer was a rare disease, no single medical center could study enough patients to make the necessary advances across the spectrum of pediatric oncologic diseases. The decision to conduct collaborative research across multiple institutions resulted in the development of cooperative group research.

In the fight against childhood cancer, this concept evolved into what is now the Children’s Oncology Group, which unites more than 8,000 experts at more than 200 leading children’s hospitals, universities and cancer centers across the US, Australia, New Zealand and parts of Europe. The group conducts research across the spectrum of cancers that afflict children and has approximately 100 clinical trials underway around the world.

With an emerging infrastructure in place for cooperative research, sustained improvement in outcomes partly reflected an ever-increasing understanding that childhood cancers are diverse. Childhood ALL, for example, is not a single disease, but rather a spectrum of diseases. Recognition of this diversity led to the study of different treatment regimens in different sub-populations of children with pathologically similar cancers.

Throughout this period, the ability to overcome the most common side effect of cancer drugs, myelosuppression (a decrease in blood counts), improved dramatically. It began with the ability to transfuse not only red blood cells into anemic patients, but also platelets, reducing the threat of life-threatening bleeding that can accompany cancer therapy.

Equally important, the risks and types of life-threatening infections that come with myelosuppression were increasingly recognized, leading to the development and better use of more effective antibiotics. Starting in the 1990s, cytokines — drugs that stimulate bone marrow to produce infection-fighting white blood cells — began to be integrated into cancer treatments, further mitigating the risk of life-threatening infectious complications of care.